ASHLESS ENGINE LUBRICANTS FOR HIGH TEMPERATURE APPLICATIONS

An ashless lubricating oil having a lubricating oil base stock as a major component, and a mixture of (i) at least one ashless antiwear additive, (ii) at least one ashless detergent, and (iii) at least one aminic antioxidant, as minor components. The lubricating oil base stock is a monoester obtained by a) reacting one Guerbet alcohol of 8 to 20 carbon atoms with a Guerbet acid, a linear or branched acid of 6 to 20 carbon atoms or b) reacting one linear or branched alcohol with at least 6 to 20 carbon atoms with a Guerbet acid of 8 to 20 carbon atoms. The lubricating oil base stock is present in an amount from 30 to 99.8 wt. % of the oil. A method for improving oxidative stability and high temperature stability of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using the ashless lubricating oil.